1. Field of the Invention
The present invention relates to techniques for monitoring the health of a computer system. More specifically, the present invention relates to a method and apparatus for determining whether components are not present in a computer system.
2. Related Art
As datacenters grow to include larger numbers of computer systems, maintaining the reliability of these computer systems is becoming an increasingly challenging task. One challenge is to ensure that “filler modules” are properly installed in the computer system to fill the empty slots that are created when field-replaceable units (FRUs) are removed from the computer system. When filler modules (which are supposed to occupy empty slots in the computer system) are not present within the computer system, the cooling air flow within the computer system can generate parasitic eddies and the temperature of the system boards adjacent to the missing filler modules can increase. This decreases the long-term reliability of the system and can also trigger temperature alarm events that can cause the computer system to shut down.
This problem can arise because service engineers, who are under pressure to swap FRUs to stabilize a malfunctioning system as soon as possible, can forget to install filler modules into empty slots within the computer system. In other cases, a computer system might be shipped without installing the filler modules into empty slots within the computer system.
One solution to this problem is to design filler modules with electronic switches so that the computer system does not boot up if the filler modules are not installed in empty slots within the computer system. Unfortunately, this solution requires extra pins and extra circuitry in the computer systems, which adds complexity and cost to the computer system, and creates new failure modes.
Hence, what is needed is a method and an apparatus for determining whether components are not present in the computer system without the problems described above.